Fe-n-based soft magnetic thin films and magnetic heads using such films

Abstract

Additive elements are added to Fe-N soft magnetic thin films along with oxygen, so that the thermal stability is remarkably improved. After annealing treatment at approximately 550° C., it is possible to provide an Fe-N soft magnetic thin film with a low coercive force. Similarly, it is also possible to provide a soft magnetic thin film having a low coercive force by introducing a combination of specific types of additive elements to Fe-N soft magnetic thin films. When oxygen is further added to the film, it is also possible to provide a soft magnetic thin film which has very excellent soft magnetic characteristics and good thermal stability. The soft magnetic thin films of the invention have good soft magnetic characteristics, a high saturation magnetic flux density and good thermal stability. A magnetic head of a metal-in-gap type using the soft magnetic thin film is also described.

What is claimed is: 
     
       1. A soft magnetic thin film which consists essentially of a composition of the formula,   (Fe.sub.a M.sub.b).sub.100-o-d N.sub.o O.sub.d     wherein M represents at least one element selected from the group consisting of Si, Al, Ta, B, Mg, Ca, Sr, Ba, Cr, Mn, Zr, Nb, Ti, Mo, V, W, Hf, Ga, Ge and rare earth elements, and a, b, c and d are, respectively, values by atomic % and are defined such that 0.1≦b≦5, a+b=100, 0.5≦c≦15 and 0.1≦d≦13.   
     
     
       2. A soft magnetic thin film which consists essentially of a composition of the formula,   (Fe.sub.i M.sub.j.sup.I M.sup.II.sub.k).sub.100-m-n N.sub.m O.sub.n '     wherein M I  represents at least one element selected from the group consisting of Al, Ga, Ti and rare earth elements, and M II  represents at least one element selected from the group consisting of Nb, Ta, V, Zr and Hf, and i, j, k, m and n are, respectively, values by atomic % and are defined such that 0.1≦j≦2.5, 0.1≦k≦2.5, i+j+k=100, 0.5≦m≦15, and 0.1≦n≦13.   
     
     
       3. A magnetic head which comprises a pair of magnetic core halves which are abutted to each other, each of the core halves including a magnetic ferrite block and a magnetic thin film defined in claim 1 or 2, which is provided on the ferrite block, the magnetic thin films formed on the respective ferrite blocks being in face-to-face and spaced relation with each other to establish a magnetic gap therebetween. 
     
     
       4. The magnetic head according to claim 3, wherein said core halves are bonded with a glass. 
     
     
       5. The magnetic head according to claim 4, further comprising a thin film of silicon oxide or silicon nitride provided, as a reaction inhibiting film, between the glass and the soft magnetic thin film and also between the ferrite block and the soft magnetic thin film of each core half. 
     
     
       6. The magnetic head according to claim 5, wherein reaction inhibiting film provided between the glass and the soft magnetic thin film is a built-up film consisting of a film of silicon oxide or silicon nitride and a film of metallic chromium or a chromium compound. 
     
     
       7. The magnetic head according to claim 5, wherein the reaction inhibiting thin film provided between the ferrite block and the soft magnetic thin film has a thickness of from 30 to 100 angstroms. 
     
     
       8. The magnetic head according to claim 5, wherein the reaction inhibiting thin film provided between the glass and the soft magnetic thin film has a thickness of from 30 to 500 angstroms.